In general, the present invention relates to a disk playback apparatus for reproducing a video/audio signal from a disk. More particularly, the present invention relates to a disk playback apparatus having a playback function for reproducing a video/audio signal from a double sided disk, that is, a disk which allows a video/audio signal to be reproduced from both surface thereof.
In addition to the single sided optical disk such as a laser disk and a DVD (Digital Versatile Disk) wherein a signal is recorded only on one surface of the disk, there is also available a double sided disk which is made by sticking two recording surfaces to each other so as to allow a video/audio signal to be recorded on the two surfaces. As is generally known, for example, a disk playback apparatus such as laser disk playback apparatus is provided with a two-surface playback function allowing a convenient playback operation to be carried out by the user on such a double sided disk. With a disk playback apparatus having such a two-surface playback function, a video/audio signal can be reproduced from both the surfaces of a double sided disk without the need for the user to severally turn the disk the other way and remount it on the playback apparatus.
By the way, in a disk playback apparatus with such a two-surface playback function, the two surfaces are univocally defined as a normal playback surface or the so-called A surface and an opposite playback surface or the :so-called B surface. When the user would like to reproduce a video/audio signal recorded on a double sided disk from the beginning but the disk is incorrectly mounted on the tray of a disk playback apparatus so that a video/audio signal will be reproduced starting from the opposite playback surface, for example, reproduction of a video/audio signal starting from the head of the disk is impossible. If the disk is mounted incorrectly so that a video/audio signal will be reproduced starting from the opposite playback surface as such, the user must carry out an operation to start a playback operation from the normal playback surface, that is, the surface opposite to the opposite playback surface of the disk. In addition, if a single sided disk is mounted incorrectly so that a video/audio signal will be reproduced starting from the non-recording surface, the user must also carry out an operation to start a playback operation from the normal playback surface, that is, the surface opposite to the non-recording surface of the disk.